Global warming

The global warming warming issue is a political battle over the science of climate change. Liberals and conservatives in the U.S. are evenly split on the issue: 75% of Democrats believe that the science supports the anthropogenic global warming theory, while only 23% of Republicans believe the science supports it.

In the general, the term global warming can be used for any upward trend in the global mean temperature, but it is mostly used to refer to the 1°F warming 1850, when the Little Ice Age ended. The two sides are divided on whether this warming is a natural recovery or the result of human activity (see greenhouse gas pollution).

Average Earth surface air temperature has risen just over 1 °C since 1850.

According to temperature reconstruction made within an evolutionary paradigm, there have been many cycles of naturally-caused global warming and cooling over many millions of years (see climate cycles). Some scientists, including Richard Lindzen of MIT, Sallie Baliunas of Harvard and Fred Singer (independent), say that the recent warming could be part of another natural cycle or random fluctuations in the atmosphere. However, a lot scientists also think that human activities were most likely the cause of the the planet's recent warming.

Assessments by the United Nations promote the view that most of the warming since around 1850 is likely human-caused. In February, 2007, the politicized Intergovernmental Panel on Climate Change, a body of scientists established by the United Nations, but whose members were appointed by their governments, released their fourth assessment report on climate change. That report concluded that most of recent global warming was "very likely" caused by human activity. It says that increases in atmospheric concentrations of greenhouse gases cause warming. Several members of this panel later complained their contributions were misrepresented in the final report.

The Hockey Stick Temperature Reconstruction

File:Hockey stick chart ipcc.jpg

The flawed Hockey Stick graph in a 2001 IPCC report shows blue proxy values along the "shaft" with red instrumental values superimposed as the "blade".

One of the main pieces of evidence for anthropogenic global warming presented during the 3rd IPCC report was a temperature reconstruction done by climatologist Michael Mann. The resulting graph of the Northern Hemisphere temperature is shaped like a hockey stick, and it is used as evidence for the unusualness of the earth's temperature in the past few decades.

While dramatic, the graph encountered serious questions from the beginning. It failed to reproduce two Northern Hemisphere climate episodes that were well documented in the literature, the Medieval Warm Period and The Little Ice Age. Concerned about these discrepancies, Stephen McIntyre and Canadian economist Ross McKitrick attempted to reproduce the result and discovered a serious flaw in the statistical methods used to construct the hockey stick graph. Because of this, the 4th Assessment Report of the IPCC included several different temperature reconstruction methods instead of favoring just one hypothesis.

Natural variability of the climate system

Evolutionary scientists who believe in global warming think that the Earth has experienced numerous ice ages over two million years, during which global temperatures dropped approximately 6 degrees Celsius and then returned to normal. The frigid temperatures allowed ice sheets to expand southward, covering much of Asia, Europe, and North America. The cooling associated with ice ages is gradual, while the terminations are relatively rapid. However, even the rapid terminations of ice ages take centuries to millennia.

Global Warming on other Planets

Since the Viking spacecraft reached Mars in the 1970s until recent readings were taken, the average temperature on Mars has risen 1.1 degrees Fahrenheit just as the average temperature on the earth has risen. Since human industrialization is clearly not to blame for the change on Mars, other causes are being considered. One possibility is that dust storms are changing the albedo of the planet, allowing it to warm, while another possibility is that solar variations from the sun are causing the warming.

Recently, it has also been found that similar to the Earth and Mars, Neptune is also undergoing global warming. Measurements taken at the Lowell observatory in Arizona have shown an increase in Neptune's brightness and temperature since 1980 following the same pattern seen on Earth and Mars. The researchers who discovered this warming suggest there may be a correlation between the warming and solar variations.

Pluto has also been found to be undergoing global warming. The overall temperature increase on Pluto has been greater than that on the earth.

Politics of global warming

The global average surface temperature warmed about 0.5 °C (0.9 °F) over the second half of the 20th Century, and to some the warming appears to be related to increases in carbon dioxide and other greenhouse gases. The possibility of adverse consequences has become a major concern for environmentalists.

Assessments of climate science by the United Nations (see IPCC - Intergovernmental Panel on Climate Change) have claimed that scientists are 90% sure that over 50% of the observed global warming in recent decades is human-caused, and that continued global warming should be expected over at least the next century. Science published a literature search by Naomi Oreskes concluding that "scientific consensus" supports the IPCC reports.

Several prominent scientists have pointed out the politicized science of the UN's assessment methods. The scientific reports are submitted to a panel of representatives appointed by each country in the IPCC. Several scientists whose research demonstrates that climate change is taking place have complained about their work being misrepresented by the U.N.

58% of the 279 climate scientists working at US federal agencies who responded to a survey by The Union of Concerned Scientists reported 435 incidents of political interference over the past five years and that they had experienced at least one of these constraints:

• “Pressure to eliminate the words ‘climate change,’ ‘global warming’, or other similar terms” from their communications.
• Editing of scientific reports by their superiors which “changed the meaning of scientific findings”.
• Statements by officials at their agencies which misrepresented their findings.
• “The disappearance or unusual delay of websites, reports, or other science-based materials relating to climate”.
• “New or unusual administrative requirements that impair climate-related work”.
• “Situations in which scientists have actively objected to, resigned from, or removed themselves from a project because of pressure to change scientific findings.”

Scientists

Roger Revelle

Roger Revelle Achim Steiner Fred Singer Richard Lindzen Sallie Baliunas Lonnie Thompson

James E. Hansen Michael Mann Charles Keeling Edwin A. Hernández-Delgado

See Also

• Does a global temperature exist?, Journal of Non-Equilibrium Thermodynamics, June 2007.
• The appliance of science by Mike Hulme.
• An Inconvenient Truth, Film by Al Gore
• The Great Global Warming Swindle - Documentary Film
• Climate Sensitivity and Observed Negative Feedbacks, lecture by Richard Lindzen and Roberto Rondanelli.
• Nature of Arguments for Anthropogenic Global Warming, by Richard Lindzen
• Hot Talk, Cold Science: Global Warmings's Unfinished Debate, by S. Fred Singer
• Global Warming: The Origin and Nature of the Alleged Scientific Consensus - Richard S. Lindzen, Alfred P. Sloan Professor of Meteorology at the Massachusetts Institute of Technology
• "Should We Have Acted Thirty Years Ago to Prevent Climate Change?", by Randall G. Holcombe.
• "After Kyoto: A Global Scramble for Advantage," by Bruce Yandle.
• The physical evidence of earth's unstoppable 1,500-year climate cycle
• "Is There a Basis for Global Warming Alarm?", by Richard Lindzen
• "New Perspectives in Climate Change: What the EPA Isn’t Telling Us"
• Survey Shows Climatologists Are Split on Global Warming
• Fighting the Hoax
• Climate Audit, Steve McIntyre's blog
• Real Climate, blog by a group of climatologists including Michael Mann

Critique of the Hokey Stick Reconstruction

• Corrections To The Mann et. al. (1998) Proxy Data Base And Northern Hemispheric Average Temperature Series by Stephen McIntyre and Ross McKitrick, Energy & Enviornment volume 14, 2003.
• The Decay of the Hockey Stick by Von Storch published on the journal Nature's blog, May 3, 2007.
• A Global Warming Bombshell by Richard A. Muller, Technology Review , Oct. 2004; calls into question famous graph by Michael Mann.
• Reconstructing Past Climate from Noisy Data by Hans von Storch, Eduardo Zorita, Julie M. Jones, Yegor Dimitriev, Fidel González-Rouco, Simon F. B. Tett, Science magazine, 22 October 2004.